Unit 2 Lecture Notes Flashcards
Why do cells replicate (divide)?
Reproduction, growth and development, tissue renewal (bone marrow r and w blood cells)
How is genetically material organized?
- chromosomes
- somatic cells
- gametes
Chromatin includes what
DNA proteins
Somatic cells undergo what
Mitosis
Somatic cells
All cells besides sperm and eggs
Gametes
Sperm and egg
Only 23 chromosomes
What are the phases of the cell cycle?
G0, Interphase (G1,S,G2), Cytokinesis, Mitotic (M) phase
G0
Resting phase
G1
Undergoing process towards S phase (unreplicated chromosomes)
G2
Cell with duplicated chromosomal getting machinery ready to undergo mitosis
S
DNA synthesis
What are the two cell cycle checkpoints and what happens during them?
G1 checkpoint: cell receives a go ahead signal
G2: cell does not receive a go ahead signal
What does the G1 checkpoint check for?
Adequate cell size, nutrients sufficient, DNA undamaged
During the G2 checkpoint what happens?
Chromosomes have replicated, DNA replicated, DNA un damaged, MPF activate and present (protein cyclinCDK complex)
What happens during the M checkpoint
Chromosomes attached to spindle, chromosomes segregate, MPF absent
What molecules turn the cell cycle on and off?
MPF contains a protein kinase (CDK) and a cyclin
Regulation of the cell cycle
- the G2-M cyclin CDK regulates entry into M
- the M cyclin-cdk regulates process through mitosis
- restriction point (R)
- the G1 phase cyclin-CDK regulates entry into the cell cycle at R
- the S cyclin-CdK regulates repair of errors in DNA replication
If DNA is damaged (blank) can bind G-S 1 CDK preventing activation by cyclin which stops (blank)
P21
Cycle in S to repair DNA
Regulation of MPF to go through G2 checkpoint
- fluctuation of MPF activity and cyclin concentration during the cell cycle
- molecular mechanisms that help regulate the cell cycle
Retinoblastoma explanation
- immature cell poliforate out of control
- genes needed for S phase not transcribed
- RB protein phosphorylated by CDK cyclin complex
- EZF - active and never shut off phosphorylation
What are some properties of cancer cells?
Environment not the cell is supposed to dictate cell division- not the case in cancer
Spread to adjacent tissues and to distant tissues through lymphatic vessels and blood vessels
Malignant
Benign
Not cancer- tumor cells grow only locally and cannot spread by invasion of metasis
Malignant tumors
Cancer cells invade neighboring tissues, enter blood vessels, and metastasize to different sites (leave!!)
